Subsea oil and gas production requires the controlled routing of produced oil and gas from a subsea wellbore, to the seabed, to a vessel, such as a drilling or workover rig, on the ocean surface. To facilitate this, offshore oil and gas operations often utilize a series of pipes that are known as risers, riser string, or riser pipe. The lower end of the riser string is connected to a blowout preventer (BOP) stack, which is an assemblage of BOPs and valves that manage the pressure in the wellbore. The BOP stack is typically mounted to a wellhead on the seabed. At the top of the BOP stack is a lower riser marine package (LMRP) that couples the lower end of the riser string to the BOP stack.
The upper end of the riser string is supported by the drilling rig, and extends to the subsea equipment (e.g., the BOP stack) through an access bay in the drilling rig called a “moon pool”. The drilling rig typically also has a rotary table and associated equipment that support and manipulate the riser string during installation. In addition, the drilling rig may carry other equipment that interacts with the riser string, such as a diverter, a spider, or a riser gimbal.
The riser string is typically constructed by securing the riser joints, which may be a flanged connection, of adjacent riser segments. Specifically, a first riser joint may be secured within and supported by a spider, with the riser gimbal supporting the spider during operation. The first riser joint may be lowered from the drilling rig into the sea, with a subsequent riser joint then secured to the first joint. In this manner, a riser string of a desired length may be formed.
Riser strings can be thousands of feet in length and, as a result, comprise hundreds of riser segments coupled together. Thus, reducing the complexity of such equipment remains a priority to reduce complications and increase efficiency when in use in the field.